code: def preprocess_fn(x: np.ndarray) -> np.ndarray:
      return x
  
file_path: alibi-detect/alibi_detect/models/tensorflow/tests/test_trainer_tf.py
imports: from functools import partial
  from itertools import product
  import numpy
  import pytest
  import tensorflow
  from tensorflow.keras.losses import categorical_crossentropy
  from alibi_detect.models.tensorflow.trainer import trainer
  from alibi_detect.utils.tensorflow.data import TFDataset
label_desc: Use image node_id 1 for calling a global function with example usage: preprocess_fn(x) and returns: x